"It was late at night and he made the decision to hit the 'delete' button because he was upset with the school district related to whatever personal reason (because of) his employment or his benefits," Lasee said. "He had malicious intent."

Carlson is a graduate of the school district and was released from his job as an information technology employee last December.

According to a criminal complaint charging Carlson with five felonies and a misdemeanor, he used the login information from a former co-worker to access the district's computer network and destroy athletics records, lesson plans, term papers and other data.

The complaint said Carlson admitted he launched an "attack" on the system after he did not receive a year's pay as part of his severance after leaving the district.

The breach did not affect students' grades, but police said the intruder gained access to a range of information, including work done by students and teachers. Some work was recovered, but some was destroyed.

We lost much of last year's school (records)," said Sgt. Thomas Schrank, a De Pere police detective.